Autism is a severe, neurodevelopmental disorder that often confers a profound burden on autistic individuals, their families, and society. Research aimed at uncovering the pathogenesis of this condition may lead to evidence based approaches to prevention or treatment, and is therefore of great importance. Strong evidence supports a genetic etiology in autism, and twin and family studies have also shown that genetic liability appears to be expressed among unaffected relatives of people with autism through features that are milder, but qualitatively similar, to the defining characteristics of autism. This constellation of subclinical language and personality features is commonly referred to as the 'broad autism phenotype'or 'BAP'. Importantly, whereas by definition autism involves serious impairment across all three symptom domains, evidence suggests that such features may decouple and segregate independently in unaffected (with autism) relatives with the BAP. Therefore, studies of relatives of individuals with autism can help to simplify the complex autism phenotype and identify component traits which are more amenable to genetic dissection than the full clinical syndrome. In this study, we focus on defining genetically meaningful language phenotypes among individuals with autism and their relatives, that may be applied in genetic studies. Using a family study design, we propose a detailed psycholinguistic assessment battery for use in families of individuals with autism and controls. This battery of objective, experimentally derived psycholinguistic measures of language processing may produce findings that throw into sharper relief current understanding of key mechanisms underlying the language impairments associated with autism and the BAP. Results will also provide quantitative measures that may be used in genetic studies, and which could be targeted in clinical intervention efforts. With senior coinvestigators with expertise in genetics, we will establish a Biobank including these rich phenotypes and DNA samples from all families that will be used for future genetic studies, and more immediately, to follow up on promising findings sure to emerge from several largescale Genomewide studies of autism underway. PUBLIC HEALTH RELEVANCE: This project aims to identify specific linguistic markers of genetic liability to autism which may be used to illuminate the pathogenesis of autism and its component features. Research aimed at uncovering the pathogenesis of autism may lead to evidence-based approaches to prevention or treatment.